US2250772A

US2250772A - Blade wheel

Info

Publication number: US2250772A
Application number: US177886A
Authority: US
Inventors: Mueller Hans; Schneider Ernst
Original assignee: Voith Schneider Propeller Co
Current assignee: Voith Schneider Propeller Co
Priority date: 1936-12-09
Filing date: 1937-12-03
Publication date: 1941-07-29
Anticipated expiration: 1958-07-29

Description

July 29, 1941. H. MUELLER I-:rAL

BLADE WHEEL s sheets-she'et 1 Filed Dc. 5. 1937 #Wi/vrom; Har/N Mvellf'r awo Arron/vf'y Meir' July 29, 1941 H. MUELLER r-:TAL 2,250,772

' vBLADE WHEEL Filed Dec. 3. 1931' 3 sheets-sheet 2 their' ATT'oRA/EY July 29, 1941.

H. MuELLl-:R nm.

BLADE WHEEL 3 Sheets-Sheet 5 Filed Dec. 3, 1937 Patented July 29, 1941 A BLADE WHEEL Hans Mueller, Heidenheim-on-the-Brenz, Germany, and Ernst Schneider, Vienna, Austria, assignors to voith-Schneider Propeller Com- Y., a corporation of New pany, New York, N. York Application December 3, 1937, Serial No. 177,886

In G

11 Claims.

This invention relates to blade wheels, and more particularly to `improvements therein. The type of blade wheels -to which this invention is an improvement is shown in Il. S. .Letters Patent No. 2,015,514 as an example.

More particularly, the invention has for its object to provide means to compensate the working effect of rearward blades of a propeller wheel in respect to the front blades, to the variations in the velocities of the water at the rear and vvfront of such propeller wheels. A further object is to sol control the swinging of the blades when near ltheir normal positions, that is, perpendicular to the diameter of the wheel at right angles to the longitudinal axis of the ship, so as to obtain the highest working effect from the blades, and also to prevent vibrations caused by rotating of the blades during too small an arc.

The invention further has for its object to provide a mechanism in which. parts rotate isochronously to each other, and in which the linkage of the parts is so correlated tothe blades that the blades follow thelaws of action hereinafter fully described.

For this purpose, the invention consists in the means for so disposing the blades that the front blades have their radii vectors intersect the diametrical line perpendicular to the length of the ship, at a point nearer to the center of the propeller than the intersection of the radii vectors with said line of the rear blades,- and that certain of the blades, those in quadrants in which said line is a median, have the intersections of the vectors with said line of the blades of the quadrant of the rearward going blades nearer to the center than the intersections of the vectors with said line ofthe blades of the -quadrant of ermany December 9,- 1936 (C1. -17o-14s) the forward going blades, considered in respect to corresponding blades along the width of the ship. By such means, the rear blades have a larger amplitude than the front blades to compensatefor the variations of velocity of the wa ter, and also the blades in the rearward going quadrant are not swungas sharply as heretofore,-

thus avoiding vibrations and losses.

Furthermore, the preferable angle 'is that delined by the formula mentioned herein.

Finally, the invention consists in the means to swing the blades and rotate thepropeller, in accordance with the laws hereinafterset forth.

The invention will be further described in the light of the embodiments thereof as shown in the drawings, and will be nally pointed out in the claims. l

In the accompanying drawings:

Figure 1 shows a diagrammatic drawing, showing the blades acting in accordance with the present; invention, in accordance with onerule of action thereof;

Figure 2 is a similar drawing, embodying an-l other rule of action;

Figure 3 is a similar diagrammatic drawing embodying the rule of action of Figure 1 combined with that of Figure 2, and forming. the present invention;

Figure 4- is a radial section to show how the parts are mechanically connected with each other, certain of the parts being shown in sideA view; and

Figure 5 is a plan view of mechanism, largely diagrammatically shown, to enablethe blades to be swung during the rotation of the blade wheel on the propeller, when acting in accordance with the laws represented in Figure 4.

Figure 6 is a horizontal section taken on line l6---6 of' Figure 4.

Figure 7 is a perspective view showing the connections of the parts, and

Figure 8 is a drawing showing the angle differential E, E being the angular difference between the largest angle in the front half and the largest angle in the rear half of the propeller.

Similar characters of reference indicate corresponding parts throughout the various views.

In accordance with the invention, there must.

be used a guiding mechanism which, as schematically shown in Figure 1, must be so designed that the radius vectors, perpendicularly erected to the blades at their pivots, in the front Apart of the rotor meet in one point N1, which is nearer the center of the wheel O than a-guiding point N2, in which the radius vectors of the blades in the rear part of the rotor intersect. The two points N1 and N2 are situated on the diameter D of the wheel whichis normal to the direction 'of now V. Onthe front part ofthe rotor the guiding point N1 ensures the control of the radius vectors and in the rear part of the rotor the control passes over to theguiding point N2.

In particular the angle between the tangential position and the blade position on the rear part ofthe rotor should be larger by a certain amount- E than the angle between the tangential position and the blade position on the front part of the rotor, -whereat the angle difference e, expressed in circular measure, should depend upon` the degree of load according to theformula merely of a number of dimensonless numbers and the value cs, which likewise has no dimenwherein S is the thrust developed by the propeller; F the swept area of the propeller; 'y the specific gravity of the water or iluidupon which the propeller works; g is the acceleration of gravity; and ve is the velocity of the iiuid when entering the propeller. To further characterize the meaning of the load factor, it may be stated that for quick moving shipswith sharp or line lines, the load factor is small (0.5 to 1.0), while propellers for blunt or full lines have high load factors to .about ten times that of Apropellers for ships with ne lines.

In case the blade wheel will be employed as a turbine, the conditions are vice versa, because the water that has been used on thefront part of the rotor flows with diminished speed to the rear part of the rotor, so that the pitch has consequently to be diminished there, if the entrance angle shall remain equal or nearly equal. Should the blade wheel be used as a pump, the phenomenon willl be the same as in case of propeller working.

The uplift of a blade is proportional to the entrance angle and the velocity of flow. If, at

a considerable factor of uplift, the vacuum exceeds an admissible amount, cavitations are likely to occur. The entrance angle and now-velocity must therefore be kept within certain limits to prevent such cavltation.

The hydraulic conditions are, however, different on various points of the circle K in consequence of the particular characteristic of the blade motion, and there is especially an essential dierence in the conditions in the region of the quadrants E-F as per Fig. 2 comparedwith that of the two quadrants F-G and H-E. These latter quadrants are limited by the diameters of wheel D1, D2 which intersect under 90 and are displaced by against the diameter D on which the guiding point N is situated. Particular attention is, however, drawn to the fact that these quadrant limits shall not be considered as exact deliminations; they are only indicated as quadrant-like regions. The conditions in quadrant region E-F are also considerably different to those of the quadrant region G-H; but it will be suiiicient if the blades in the quadrant region G-H are suited to the relative flow.

In the quadrant E-F the blades make a very quick turning movement. If one desires to maintain admissible angle values in the quadrant E -F, the pitch must be limited in this quadrant. The guiding point adjusted at N, according to Figure 2, for the quadrant E-F must approach the center O of the bladeiwheel and be displaced for example to N3, as shown in Fig. 2. .This can be done in sucha degree that evenoin the case.

of a large pitch of the blades travelling'V along the quadrants F-G and H-E, the entrance anf gle for the blades travelling along the quadrant -E-Fwill remain within admissible limits. It is therefore possible, incase of high speed of the ship, to increase the pitch in the front and the rear quadrant in order to diminish the rotational velocity. This can go 'so far that the guiding point N of Fig. 2 for the blades travelling along .positions N and Na.

is, according to Fig. 1, the intersection for the' rear part of the rotor.

the front and the rear quadrant moves o in the .center O-of the wheel that it comes on the circle K or even out 'of it.

The nearer the guiding point N3 will be approached to the center 0.o! the wheel, the smaller becomes the pitch of the blades in the quadrant E-F, and in case' of exceeding a certain limit of approach of the point N3 to the center of the wheel, the blades in the quadrant E-F Will act as turbine blades, namely by the fact that they will be driven lby the water flow provo'cated by the bladesin the front and rear quadrant. This may be desirable incertain cases.' as it has already been proposed to reduce, in case of screw propeller, the pitch of the propeller blade towards the boss by such an amount that they Work as turbine blades in the region of the boss or hub.

In the sense of the present invention, the intersection of the radius vectors with that diameter of the wheel which is in a normal position to the direction of the flow, will move to and fro for .every blade at any working condition within certain limits i. e., in the sense of Fig. 1, for example between the position N1 and N2 and in the sense of Fig. 2 for example between the For propeller service, N1

blades covering the front partof the rotor, and N2 .the intersection for the blades covering the As per Fig. 2, N is the intersection for the blades covering the front and rear quadrant, and N3 is the intersection for the quadrant E-F situated at the side of the eccentricity of the intersections N1 and N2 of Figure 1, or N and N3 of Figure 2. It is, however, not necessary at all that the points N1 and N2 of Fig..

ure 1, or N and Ns of Figure 2/remain stationary for more or less of the large regions of the circular path of the blades: the intersections can also change their position from point to point 'of the blade circulation,'but always by observing the explained principles. 'Ihe intersections will therefore change their position within certain limits durin'g every revolution of the blades in the sense of Figs. 1 and 2 i. e.of course for every blade in the same way and by the same measure. N ow, it is advisable to put into effect at the same time the two rules of motion which are represented in Figs. 1 and 2, on one and the same blade wheel, to superpose two rules. For propeller service, the pitch on the front part of the rotor should be smaller than on the -rear part (Fig. 1),

in the quadrant but on theother hand, the pitch E-F on the side of the eccentricity should be smaller at the same time than lthe pitch in the front,- and rear belonging to the upper quadrant E-F (i. e. to

that on the side of the eccentricity of all intersections) havehowever still received the index 3, so thatv these two intersections are marked with Ni?. and Nz3.

Instead of 'a guiding point for a certain working condition, there are regions of lintersections withinthe limits of which the intersections move durmg the revolution of the blades for a certain working condition, i. e. by pumpsror progressively.

'I'hese regions can be displaced both diametrically and in the circle, in case the working conditions shall be changed.

The same. applies also to any other use of such` a blade wheel, i. e. also to such a blade wheel pump or blade wheel turbine.

If a -desired position yof a blade on any point of its circular path has been found as most favourable from the hydraulic viewpoint in accordance with the foregoing, it is not diiilcult to respectively. In the quadrant E-F the blades move from front to rear, and this quadrant may be called the rearward going quadrant. The quadrant G-H may be called the forward going quadrant. The quadrant H-E may be called the front quadrant, and the quadrant F-G may be called the rear quadrant. The diametrical line perpendicular to the longitudinal axis of the ship is a median line to the forward and rearnd a kinematic device which will be able to positively guarantee the positions of the blades. This can be done by means of correspondingly formed guides (or guiding systems); but itis also possible to enforce such motions by means of corresponding steering mechanism.

Figs. 4, 5, 6 and 7 show as an example a method of construction of a guiding mechanism suitable for the realization of the combined rule of motion.

an arm of an angle lever, the centre of rotation 6 of which is located on the wheel and the second link 1 of which is guided in a slot guide The pivot l of each blade 2 is yfixed to a lever 3 to which is pivotally connected a rod I the,- -other end of which is pivotally connected with with the teachings of the foregoing.

It is not desired to be limited to the embodiments, as changes can be made therein without departing from the spirit of the invention as de' fined in the annexed claims.

8. This sloty guide 8 is mounted on a ring 9 turnable round on axle center Il, which is parallel to the pivot axle l0 of the wheel. The ring 9 can be displaced against the wheel in radial direction and in addition, its center II can also be turned round the pivot I0. By diiferentadjustments of the center Il of. the ring Q in respect to the pivot l0, the Working condition of the blade wheel can be lchanged.

Upon turning of the wheel, the ring 9 must be nously rotary motion of the wheel and the ring 9, the guiding mechanism -of each of the blades Works as shown in Figure 5, so that the blades induced to turn isochronously. At this isochr- I will eiect motions as represented in Fig. 3. The

. radius vectors indicated with dotted lines in Fig.

5 cross the wheel diameter D in .differentpoints as shown, i. e. according to the rule of motion.

In Figure 5 there are shown-six N .points or intersections instead of the four shown in Figure 3.

The arm 5 is longerthan the lever 3 and the length of the lever 3 and the length of the rod l have been so selected that the

arms

3 and 5 converge towards the pivots l and 6 in the most of positions. It results from the diiferenceof the length of the

arms

3 and 5 that the load of the blades will be increased compared with similar guiding mechanism at which the

arms

3 and 5 would have the same length. The mentioned convergence of these two arms induces the special distribution of the different loads as represented in Figure 3. The point in question is therefore to increase the derived motion of the y arm 3 and 'consequently of the blade 2 compared with the guiding motion of the. arm 5 and to furthermore provoke the necessary irregularity of the motion transmission.

The method of construction represented .in Figure 5 shows that it'i's possible by relatively simple meansto realize the above described blade motions from. which it results that guiding mechanisms and transmission means of other kind can be made suited for the enforcement of such blade motions. f

'In Fig. 2, the orbit of the blade rotation is divided into four quadrants by two diametrical lines connecting points E and G, and F and H,y

We claim:

1. A bladewheel propeller having blades -substantially parallel with the'axs of .rotation of the propeller and adapted to rotate in a circular orbit and to swing round their axes during the rotation of the propeller, means for rotating the propeller, means for swinging the blades of the front half of the propeller around their axes during the rotation of the propeller to increasing angles from a tangential position of the blade to decreasing angles to 'another tangential position, in respect to a predetermined largestangle in the front half of the propeller, means for swinging the blades in the rear half of the propeller to l'increasing angles from said last named tangential position of the blade to decreasing angles to said first named tangential position, in respect to a predetermined largest angle in the rear half of the propeller, and means for coordinating the working of the` aforesaid two me'ans so that the' predetermined largest angle in the rear half of the Apropeller larger than said predetermined largest angle in the front half of the propeller, said means including a connection with each blade and an eccentric,` to the propeller wheel operating said connection. A

2. A blade wheel lpropeller having blades substantially parallel with thel axis of rotation of the propeller and adapted to rotate in a circular orbit and to swing round their axes during the rotation of the'propeller, means for rotating the propeller, means for swinging the lblades of the frontv half of the propeller around their axes during the rotation of the propeller to increasing angles from a tangential position of the blade to decreasing angles to another tangential position, in respect to a predetermined largest angle t in the'front half of the propeller, means for swinging the blades in the rear half of the propeller to increasingA angles from said lastnamed tangential position of the blade to decreasing -a'ugles to said firstnamed tangential position, in respect to a predetermined largest angle in the rear half of the propeller, and means for coory dinating the working of the aforesaid two means that the predetermined largest angle in the` rear half of the propeller islarger than said predetermined largest langle inthe frontv half of the propeller by an amount e, this amount exwith the formula 0,01.j1c. 0,06.1/1c..--,

said means including a connection with each blade and an eccentric to the propeller wheel operating said connection.

. 3. A blade wheel propeller having blades substantially parallel with the axis of rotation of the propeller and adapted to rotate in a circular orbit'and to'swing round their axes during the rotation of the propeller, means for rotating the propeller, means for swinging the blades of the front half of the propeller around their axes during the rotation of the propeller to increasing angles from a tangential position of the blade to decreasing angles to another tangential position, in respect to a predetermined largest angle in the front half of the propeller, means for swinging the blades in the rearhalf of the 'propeller toincreasing angles from said last named tangential position of theblade to decreasing angles to said rst named'tangential position, in respect to a predetermined largest angle in the re'ar halflof the propeller, and means f or coordinating the working of the aforesaid two means so that the predetermined largest angle inthe rear half of the propeller is larger than said pre-I determined largest angle in the front half of the propeller, said means including a connection with each blade and an eccentric to the propeller Wheel operating said connection, said swinging means including means disposing the blades to the front and rear halves so that radii vectors of the iront blades intersect at a common -point nearer the center of the propeller than the common point o f intersection of radii vectors of the 2,250,772 pressed in circular measure being in agreement median, and in which the blades move rearwardly sothat their radii vectors intersect at a point nearer thel center of the propeller than the intersection "of the radii vectors oi the other blades.

5. A blade wheel propeller having blades substantially parallel with the axis of rotation of the propeller and adapted to rotate in a circular orbit and to swing round their axes during the rotation of the propeller, means for rotating the propeller, means for swinging the blades of the fr`ont half of the propeller around their axes during the rotation of the propeller to increasing angles from a tangential position of the blade to decreasing angles to another tangential position, in respect to a predetermined largest angle in the iront half of the propeller, means for swinging the blades in the rear half of the propeller to increasing angles from said last named tangential position of the blade to decreasing angles to said rst named tangential position, in respect to a predetermined largest angle inthe rear half of the propeller;` means for coordinating the Working of the aforesaid two means so that the-predetermined largest angle in the rear half of the propeller is larger than said predetermined largest angle in the front half of the propeller, said means including a connection with each blade, and an eccentric to the propeller wheel operating said connection, said swinging means including means disposing the blades to the front and rear halves so that radii vectors of the iront blades intersect at a common point nearer the center of the propellerthan the common point of intersection of radii vectors of the corresponding rear blades, said correspo'ndence of blades being considered in respect to the length of the corresponding rear blades, said correspondence l of blades being considered in respect to the length of the ship.

4. A blade wheel propeller having blades sub- Y stantially parallel with the axis of rotation of the propeller and adapted to rotate in a circular orbit and to swing round their axes during the rotation of the propeller, means for rotating the propeller, means for swinging the blades of the front halt of the propeller aroundy their axes to a predetermined largestangle in the vrear half of the propeller, means for coordinating the ship, and means for swinging 'the' blades in thatA quadrant of the orbit in which the diameter of the orbit perpendicular to the shipsaxis is a median, and in which the blades move rearwardly, so-that the intersections of the radii vectors with the said median are nearer to the center of during the rotation of the propeller to increasing working of the aforesaid two meansoso that the I predetermined largest angle in the4 rear half of the propeller is larger than said predetermined largest angle in the front half of the propeller, said means including a connection withv each blade, and an eccentric to the propeller wheel operating said connection, said swinging means including means disposing the blades to the front and rear halves so that radii vectors of the front blades intersect at a common point nearer the center of the propeller -thanthe 'common point of intersection of radii vectors of the corresponding rear blades, `'said correspondence of blades being considered in respect to the-length of the ship, and means for swinging the blades in' that Y quadrant of the orbit in.' which the diameter or -the propeller for the blades moving in said rearward moving blade quadrant than the intersections of the radii vectors of the other blades.

6. A blade wheel propeller having blades substantially parallel with the axis of rotation of the propeller andadapted to rotate in a circular orbit and to swing round their axes during the rotation of the wheel propeller, means for rotating the propeller, means including an eccentrcally adjustable ring, means rotating said ring isochronously with the wheel of the propeller, a guiding device, one for each blade turnably mounted on said ring, elbow levers 4pivotally mounted at their angular partson said wheel, one leg of each of said levers being guidingly connected with each guide device, the other legs having free ends, rods iixed to the blades at an angle to the longitudinal axes of the blades and having free ends, and links connecting the free ends of said elbow levers and the free ends of the rods, the length Q1' each leg of the elbow levers connected with the links, being longer than the lengthof the blade rods, and the length of the links being such that when in the position corresponding to that of the blades in tangential position to said orbit, the said other leg and blade ro'd converge in the direction towards the pivot of the said other les.

7. In a blade wheel propeller having blades substantially parallel with the axis of rotation of the propeller and adapted to rotatein a circular orbit and to swing round their axes during the rotation oithe propeller, means for rotating the propeller, means including an eccentrically ad- .iustable ring, means rotating said ring isochronously with the wheel of the propeller, a guiding device, one for each blade turnably mounted on said ring, elbow levers pivotally mounted on said wheel at the angular parts thereof, one leg of each of said levers being guidingly connectedspending to that of the blades in tangential position to the said orbit, the said otherlegandblade rod converge in the direction towards the pivot .of the said other leg, the amplitude of swinging of the swinging movement of the eblow levers being less than the amplitude of the swinging movement ofthe blades.

8. In a blade wheel propeller having blades substantially parallel with the axis of rotation of the propeller and adapted to rotate in a circular orbit and to swing round their axes during the rotation of the propeller, the orbit of the blade rotation being divided into four quadrants, with a diametrical line passing through the axis of rotation of the propeller perpendicular to the thrust produced by the propeller when the direction of thrust is in line with the ships axis as amedian to two opposite quadrants, one of the last named quadrants being for the rearward going blades, means disposing the radii vectors of the blades of the rearward going quadrant to intersect with said median line, means disposing the radii vectors of the blades through the'remaining quadrants to intersect with said median line and means coordinating said two means so that the points of intersection of the second.. named radii vectors are at points further from the axis of theepropeller than the points of intersection of said iirst named radii vectors.

9. In a blade wheel propeller, the combination of a blade substantially parallel with the axis of rotation of the propeller and pivoted thereto,l a

lever for said blade for moving it on its pivot, and having a free end, an elbow lever having a free end, a shiftable guide for the other lever of the elbow lever, a pivot on the propeller for the corner of the elbow lever, and a. link pivotally connecting said free ends of the rst lever and of. the elbow lever, the length of the link being such that the rst lever and free end of the elbow lever converge towards each other and towards the pivots of the rs't and secondlevers at the blade and at the propeller.

10. In a blade wheel propeller, the combination of a blade substantially parallel with vthe axis of rotation of the propeller and -pivoted thereto, a lever for said blade for moving it'on its pivot, and having a free end, an'elbow lever, having a free end,fa shiftable guide for the other lever of the elbow lever, a pivot on the propeller for the corner of the elbow lever, a link connecting said free ends of the rst lever and of the 'elbow lever, the length of the link being such that the levers converge towards each other and towards the pivots of the iirst and second levers, at the blade and at the propeller, and means to actuate the shiftable guide, said means including a shiftable center for slidingly controlling the angular position of said shiftable guide relative to a, radius of the propeller during its rotatio about its axis.

11. In a blade wheel propeller, the combination of a wheel, a plurality of blades supported thereby adapted to move in an orbit upon the revolution of the Wheel, a lever Yfor each blade, a ring shiftable eccentrlcally in respect to the orbit of said blade, an elbow lever connected at its angle with the wheel and at one leg with the ring, a link connecting the lever on the blade with the other leg of the elbow lever for swinging the blade upon the movement of the ring while the -blades are moving through their orbit, and' `means for rotating the ring in respect .to'the Wheel, whereby upon the rotation of the 4,wheel and the ring, the varying position of the ring controls the swinging action of the blades while moving in its orbit.

HANS MUELLER. ERNST SCHNEIDER..